Lanyard operated, delay arming mechanism



Jan. 12, 1965 A. M. SAUNDERS LANYARD OPERATED, DELAY ARMING MECHANISM Filed May 8, 1962 INV EN TOR.

ALLA/V M. SAUNERS ATTORNEYS invention;

United States Patent Gftice l PatentedJan. 1.916,5

3,165,059 LANYARD OPERA'IED, BELAY ARMING MECHANSM Allan M. Saunders, 3024 Price Court, vPalo Alto, Calif.

Filed May s, 1962, ser. No. 193,137 Y 6 Claims. (Cl. 162-83) Y vThis invention relates -to high explosive initiator mecha-l nisms and particularly to theV` type sometimes referred to as destructors or igniters of the kind used in missiles and bombs.

It is conventional practice to initiate explosives with series or train of smaller charges such asa primer Vwhich initiates a booster or percussion detonator which in turn initiates the main charge. The primer'is initiatedv electrically by closing of an electric circuit so that breaking or shorting of the circuit is effective to prevent tiring the booster and main charge. explosive charges, electrical isolation is not alone depended upon for safety but pyrotechnic isolation is also required for absolute safety in the event of failure of electric circuits to perform as intended. This has beenk accomplished in some typesof initiators by supporting one or more charges of the explosive initiating train in a rotary or otherwise movable member so that it may be'moved out of adjustment or registry with the other charges and its accidental detonation willv not be communicated through the train to main charge. In such devices, it is usually necessary to perform ya manual cocking of the mechanism so that the movable member will move into registry after release of a bomb or launching of a missile in response to the action of a timing mechanism in the bomb or missile or in some cases in response to radio control from the launching base or vessel.

It is the object of the present invention to effect arming of an explosive device in a missile or bomb by what may be termed an umbilical cordor lanyardl forming a connec- CII However in handling of large l tion between the safe-ann mechanism within the missile and the base or launching vessel, the separation of which connection produces the required energy, or automatically performs the cooking necessary, to cause the desired change from safe to arm position. *l

A further object of the invention is to provide means by which the actual arm position is delayed for a predetermined time period after such separation for protection against premature detonation.

A further object of the invention is to provide means for manual connection of the lanyard to the missile which will insureestablishment of the safe position irrespective of whether the mechanism was in its arm position or in some position between safe and arm.

A further object of the invention is to provide a positive spring force and lock to hold the mechanism in the safe position in spite of jolts and vibrations and possible broken parts resulting therefrom until such timeas the missile or bomb is launched.

A further object of the invention is to provide va positive spring force and lock to hold the mechanism in the armed position once that position has been achieved, in spite of vibrations and jolts and possible broken parts reis a part of the mechanism disclosed in FIGpl carrying a percussion detonator and electric detonatorA or primer associated therewith; and

FIG. 3 is a sectional view illustrating means for connecting a lanyard with the safe-arm device as well as latch means and means for sealing the device against the entrance of dirt or other foreign matter into Athe area of its working parts.

The drawing is purposely schematic to clearly illustrate the principles of the invention without disclosing parts which are not pertinent theretosuch as electric circuits and housings, the design of which are within the skillV of those familiar .withV the art and whichmay be changed in adapting the inventionA to missilesiand bombs ofvarious types.

c i In FIG. 1 ofthe drawing, a timer spring is shown at 10 Y and a rotor actuating spring is shown at 11. A rotor 12 is positioned adjacent an electric detonator or primer 13 which is fixed with respect'to the vrotor as bya housing part shown at 14 in FIG. 2. The rotor has a transverse 50 to effect alignment ofthe percussion detonator with the primer in a well known manner. The springs 10 and 11 which are, in the safe position of the rotor, not under tension are tensioned by retractionzfromthe device of a rack 1S (see also FIG. 3). The rack 18 meshes with a gear 19 on a shaft 20 ,andthe shaft 20 is connected to a timer shaft 21 by meanslof the spring 1t).` The gear 19 meshes with a gear 22 on the shaft 23 which is connected by the spring 11 with aV rotor shaft 24 lixed to the rotor 12.

:Consequently upon retraction of the rack 18, both gears 19 and 22 are-rotated to tension spectively. Y

When spring 10 is Atensioned, itimmediately tends to rotate the timenshaftZll. This shaft carries a gear 25 in mesh with the pinion 26 which drives a Atimer orescapement mechanism contained within the housing 27; VThe springs 1 0 and 11, re-

escapement mechanism is of conventional Vtype VVandl need not hereinbe illustrated in detail, Its purpose, however,` f is to limit the speed of rotation of the timer shaft 21 soV th'atitNwill ,requirea,predeterminedperiod of time, say

twenty seconds, fr thisshaftto turn a disc 29 of a Geneva or other type latch which normally prevents rotation of therotor'12. VIn its latching position, thedisc 29 registers with a notch 30 in the rotor 12 and, upon rotation of disc` 29 to the position where a notch 31 therein registers with the rotor, the rotor is free to turn and is quickly turned sulting therefrom, until suchA time as the lanyard might be reinstalled. l

Still further and more specific-'objects are made4 apy in accordance With the present FIG. 2 is a central sectional view Vof a safe-arm mechanism view through a rotorfwhi'chl through by the tension of spring 11 until a lug 32 on the rotor comes to rest against a fixed stop 33.- This effects alignment of the percussion detonator with they primer and main charge so that the initiator is in its arm positionand closing of a circuit to the primer 13 will allow detonation of a main charge 16. The circuitv (not shown). tothe primer 13"may itself be controlled by timing'A mech- 1 i anisrn" or by conventional-radio controlslfrom a launching', v baseor vessel.

. vRetraction of SSinFlGf. 3 connected by a lanyard pin 36 with the outer ananas Y vthe rack 18 from the safefpositionpf FIG, l to the arm position represented in FIGfSjimay be "accomplished by a lanyard, a part of whichv is shown at pin at the armed position shown in FIG. 3. Consequently upon launching of the missile when the lanyard becomes taut the rack is retracted to arm the mechanism and the separation ofthe lanyard is acected.

lt is of course necessary to retain the rack in its retracted position in order to prevent the tension of the springs from immediately returning it to its original position. This is accomplished by a spring latch as shown at 42 in FIG. 3 which engages a projection 43 on the ratchet when it is retracted. The mechanism may be placed in safe position at any time by insertion of the lanyard pin 36 to the position shown in FlG. 3 and then by further forcing the pin inwardly until it rst strikes and disengages the spring latch 42 and then forces the rack inwardly to the safe position shown in FIG. 1.

Failures have been encountered in previously known safe-arm mechanisms which have been attributed to chips of metal or dirt finding their way into the mechanism and the present mechanism may be installed in a sealed case of any suitable sort and further protected by a iexible seal which may be of the bellows type as shown at 45 in FG. 3. This seal permits reciprocal movement or" the rack without admitting airborne contaminants to the mechanism, The seal is also effective against air or vapors so that the housing containing the mechanism may be charged with an inert gas to prevent the entrance of moist atmospheric air which at high altitudes and low temperatures results in ice particles which might cause rust or otherwise interfere with reliability of operation.

It is preferable that the springs 1@ and 12 be tensioned toward the safe position when the mechanism is inthe safe position and that retraction of the rack 18 impose somewhat more than sufficient load to effect driving of the mechanism to its arm position. Consequently if the rack be reinserted, the springs will be returned to their safe position. Furthermore if in the event that the rack be inserted when the tension of the spring 1li is partially spent reinsertion of the rack will return the spring to its normal safe position imparting torsion or a load thereto toward the safe direction. This load will tend to reverse the direction of the timer shaft Z1 and the same reverse torque in the spring 11 will tend to reverse the direction of the rotor 12 so that the springs will serve to bring all parts of the mechanism to their normal safe position.

In the present disclosure a single timer mechanism and single rotor actuating mechanism have been disclosed but it is contemplated that these mechanisms may be duplicated to the end of further insuring reliability. Thus identical springs, timer, shaft, rotor and associated parts such as disclosed in FIG. 1 can be placed on the opposite sides of gears 1.9 and 22 so that in the event of failure to fire of the primer or percussion detonator of one-half of the mechanism the identical parts of the other half may insure detonation of the main charge.

Other arrangements of gears and latches could be used to serve the Asame objects depending on space requirements of the particular installation.

The escapement mechanism 27 could be omitted and replaced with a latch which would be released by radio control, or with an acceleration operated latch which would be released by acceleration of a missile.

The term missile as used in the appended claims is to be understood as including bombs and other devices which might carry explosive components. Similarly launching is to be taken or lncluding releasing or dropping and the term base is intended to include any vessel such as a ship or plane from which explosive devices might be launched or released.

l claim:

1. in a sate-arm explosive initiator for missiles and the like, a spring actuated arm mechanism, a latch normally preventing movement of the arm mechanism from sate to arm position, spring driven means to release the latch, a pair of rotatable shafts connected one with the arm mechanism spring and onewith the latch spring, meshing gears connecting said shafts, a reciprocable rack bar meshing with one gear, a lanyard connecting said rack `bar with the missile base whereby upon launching of the missile the lanyard will impart movement to the rack bar and tension both of said springs. i

2. The combination of claim 1 with means for retaining the rack bar in its spring tensioning position.

3. The combination of claim 2 in which the lanyard is connected to the rack bar by a lanyard pin releasable from the rack bar after it has been actuated.

4. The combination of claim 3 with means on the lanyard pin for releasing the rack bar retaining means when the lanyard pin is connected with the rack bar.

5. rlhe combination of claim`3V further comprising a housing part through which the reciprocal rack bar extends, and a ilexiole seal between lthe rack bar and housing part to exclude contaminants from the housing.

6. In a safe-arm explosive initiator mechanism for missiles, a rotary member. movable from a safe to an arm position, a spring for moving said member, latch means normally preventing movement of said member, a time controlled rotary' shaft, means on said shaft for releasing said latchmeans after a. predetermined rotary movement of the shaft, a second spring for imparting rotation to said shaft, andmeans forming a connection between the missile base and the initiator to tension both of said springs. A'

References Cited in the file of this patent UNITED STATES PATENTS 1,385,598 Weed Iuly26, 1921Y 1,512,249 Sprague et al Oct. 21, 1924 2,922,340 Wilkie Jan. 26, 1960 2,978,982 Bianchi Apr. 11, `1961 2,996,989 Grandy Aug. 22, 1961 FOREIGN PATENTS 233,262 Great Britain May 7, 1925 685,607 France Apr. l, 1930 

6. IN A SAFE-ARM EXPLOSIVE INITIATOR MECHANISM FOR MISSILES, A ROTARY MEMBER MOVABLE FROM A SAFE TO AN ARM POSITION, A SPRING FOR MOVING SAID MEMBER, LATCH MEANS NORMALLY PREVENTING MOVEMENT OF SAID MEMBER, A TIME CONTROLLED ROTARY SHAFT, MEANS ON SAID SHAFT FOR RELEASING SAID LATCH MEANS AFTER A PREDETERMINED ROTARY MOVEMENT OF THE SHAFT, A SECOND SPRING FOR IMPARTING ROTATION TO SAID SHAFT, AND MEANS FORMING A CONNECTION BETWEEN THE MISSILE BASE AND THE INITIATOR TO TENSION BOTH OF SAID SPRINGS. 